This section is not intended to provide a comprehensive overview of drug use other than tobacco, but to demonstrate that the deliberate inhalation of smoke from the combustion of any matter is injurious to the health, whether it contains nicotine or not. Health effects of smoking any substance will depend on the age at which smoking commences, the duration for which the body is exposed to the smoke, and the concentration and nature of constituents of the matter smoked.
The scientific literature describing the health effects of smoking tobacco is comprehensive because of the relatively large proportion of the population which has used tobacco, the time period over which tobacco has been consumed, and the fact that the legality of tobacco has not inhibited respondents from answering questions about their consumption.
This cannot generally be said of the smoking of other substances, which are either illegal in many societies, or are smoked by sub groups too small and scattered to have been the subject of epidemiological studies. The other major inhibiting factor for research is adequate funding. However the following observations may be made:
Herbal cigarettes are sometimes posed as a 'safe' alternative to smoking. Some may even claim healthy properties, and are sold in health food shops. However some varieties, particularly brands of Chinese origin, are blended with tobacco, these apparently having tar levels varying between 11 and 15 milligrams and nicotine levels of around 1.5 milligrams.(178) This places them at the uppermost levels of tar and nicotine content set by federal government regulations for tobacco cigarettes manufactured in Australia. Brands which contain no nicotine nevertheless have similar levels of tar and particulate matter to tobacco cigarettes, suggesting that they too are harmful to health.(179)
Kreteks are cigarettes containing a combination of shredded clove buds and tobacco. Originating in Indonesia, where they are the most popular type of cigarette, a small number of brands are imported into Australia.
The American Medical Association reviewed the medical evidence concerning clove cigarettes in 1988 and reached the following conclusions(180):
1. Clove cigarettes are tobacco products. They therefore possess all the hazards associated with smoking. In addition, inhaling clove cigarette smoke has been associated with severe lung injury in a few susceptible individuals. Patients with a history of asthma appear to be at increased risk for inhalation of clove cigarette smoke. Respiratory tract infections may increase the risk from inhalation of clove cigarette smoke.
2. Some individuals with normal respiratory tracts and normal pulmonary function may suffer pulmonary aspiration as the result of a diminished gag reflex produced by a local anaesthetic action of the eugenol contained in clove cigarette smoke.
Bidis are the traditional manner of smoking tobacco in several countries, especially India, Nepal and Bangladesh. Bidis consist of sun dried and cured tobacco flakes, rolled into a piece of dried leaf. In those countries where their use is prevalent, smoking of bidis is major cause of oral and respiratory cancers, heart and arterial diseases.(181)
Indian manufactured bidis are currently available in Australia through at least one importer.(182)
Cannabis is the most frequently used illegal drug in Australia, with around 30% of the adult population and around half of the population aged between 20-39 years claim to have tried it at some time.(4)
Marijuana contains a combination of the dried leaves, flowering tops and stems of the plant Cannabis sativa. Hashish is the resin from the flowers of the plant.
In addition to cannabis-specific compounds, the smoke from burning marijuana contains carbon monoxide and established carcinogens benzopyrene and benzanthracene.(3,4) There are no reliable long term studies on the health effects of regular use of cannabis. However it is known to cause a wide range of physical effects (in addition to its euphoric effects), including impaired airways clearance, increased cellular abnormalities in the lungs, and increase heart rate.(4)
Refer to Chapter 9 for information on smokeless tobacco.